Brake control system



March 14, 1944. H T LAMBE 2,343,984

BRAKE CONTROL SYSTEM Filed Oct. 31, 1941 2 Sheets-Sheet 1 /e0 Ml a kw A?! /04 ii (ID Gb 724 4 March 1944- H. T. LAMBERT 2,343,984

BRAKE CONTROL SYSTEM Filed 001;. 31, 1941 2 Sheets-Sheet 2 I INVENTOR 72 H0276) 7. 'Aany}erf.

substantially'along the line 2-4 of Fig. 1;

Patented Mar. 14, 1944 con'raor. SYSTEM Homer '1'. Lambert. St. Joseph. Micln. assignor to The LambertBrak e Corporation, St. Joseph, higan Mich., a corporation of Mic Application October 31, 1941, Serial No. 417,308

6 Claims. (01. 180-18) The present invention relates to tractors and particularly relates to improvements in the means for facilitating the steering thereof by selective application of the brakes. In certain respects, the present invention relates to improvements over the construction disclosed and claimed in the copending application of Homer '1. Lambert et 9.1., Serial No. 359,766, filed October 4, 1940, now Patent No. 2,264,537,,issued December 2, 1941.

One of the primary objects of the'present in-- vention is to provide improved means to facilitate the making of sharp turns with a tractor by selective application of the brakes.

Another object of the present invention is to provide improvements in devices of the type mentioned in which the brakes are fluid actuated and in which there is no leakage in the system, particularly through the control valve.

Another object of the invention is to provide improvements in controls of the type mentioned in which the controls are automatic and positive in their action.

A further object of the invention is to provide improvements in controls of the type mentioned, so that the tractor is adapted for properoperation under various conditions, such as normal work conditions, when one or the other of the wheels is in the mud or in a rut, and when driving on a highway.

Another object of the present invention is to provide improvements in controls of the type i mentioned in which any bank of pressure in the elf-brake will force the metal ball elementof the i valve away from its seat just enough to permit the surplus fluid to be released, thereby preventing heating or drag in of the brake on eithe side.

Another object of the invention is to provide an actuating means which may be adjustably set for operation at various radii of turns.

Other objects of the invention will become apparent from the following specification, the drawings relating thereto and hereinafter set forth.

In the drawings, in which like numerals are used to designate like parts in the several views throughout:

Figure 1 is a side clevational view of a conventional form of tractor, with parts broken away to show some of the interior constructions'and embodying the brake control means of the present invention;

Fig. 2 is an enlarged cross-sectional view taken Fig. 3 is a cross-sectional view taken substan-- tially along the line 3-4 of Fig. 2;.

Fig. 4 is a vertical cross-sectionalview of a master cylinder and control valve assembly illustrative of thepresent invention;

Fig. 5 is a cross-sectional view taken substantially along the line H of Fig. 4; and,

Fig. 6 is a side elevational view of the control valve of Fig. 5 and dlagrticaliv illustratins the wiring diagram-thereof.

Referring to the drawings. a conventional tractor is illustrated in Fig. 1. such tractor having a pair of driving wheels I 0, one at each side of a transverse axle ll, mounted at the rear thereof. Only one of the driving wheels is appears in the view, the other being broken away to show some of the interior construction. The tractor is provided with front wheels l2, which are mounted in any conventional or suitable manner for steering. and the wheels I! are steered by a steering wheel it, which acts through a steering arm I and rod II in the usual manner. Each of the rear wheels of the tractor is provided with an hydraulic brake (not shown), which may be of any desired form and construction, but is preferably of the type disclosed in the Homer T. Lambert Patents Nos. 2,063,444, 2,099,489, 2,161,359 and 2,161,360.

The brakes of the rear wheels are ene gized by a master cylinder-assembly. shown best in Fig.

opening closed by a removable plug 22.

A brake operating pedal 23 (Fig. 1) is pivoted on a brake shaft 24, which extends into the reservoir it and carries an arm 25, which is connectedby pin Iiand'apushrodlltoabrake' actuating piston 29 positioned within the bore II. A suitable spring 29 seats at one end against the casting I. and at the other against a shoulder on the push rod 21, thereby acting in a direction to return the pedal to release position.

The piston 28 is provided with a rubber disc 30 on its forward. face adapted to seal it against leakage between the piston and the cylinderwall.

66 There is provided, however, a plurality of communicating passageways ii, I2, and a central bore a by means of which fluid may, under certain circumstances, flow through the piston. Extending into the central bore 33 of the piston 1 is a valve rod 34, having its rlghthand extremity,

I I5,iorcing it-against the pistomthereby acting to maintain the valve closed and at the same over the end 01 the corresponding core. thus blocking the passage into conduit I4 or I, depending oi course upon which coil is energized.

Non-magnetic, metal, tubular bushings II and III, which are relatively, thin, are pressed into the inner ends of the cores it and 52, respectively, so as to prevent the metal ball from adhering to or sticking to its seatwith respect to the cores ll time to urge the piston 28 toward brake releas position. I

The leithand extremity of the valvev rod 34 is guided by means of a spider ll, having a plurality of legs 3!, there being three or such legs in the embodiment described, against the out-turned extremities of which seats the spring 31. A snap ring 40 is seated within a suitable groove in the leithand extremity oi the valve rod 34 and acts to limit movement of the valve rod to the right under the influence of the spring 31. The parts.

are so proportioned that when the foot pedal is released, spring 20 shlftsthe pedal and the piston 2' far enough to the right so that a slightopening of valve 25, it occurs. Asa result, when the brakes are in release position, fluid may flow from. reservoir it through passages 3i and 32 and bore 33 to the lefthand side of piston 38, thereby compensating for any leakage which might occur in the pressure lines to the brakes.

The bore I1 is connected by a counterbore 4| to the interior oi. the valve IS. The valve is is 0! the electromagnetic type and includes a nonmagnetic valve body portion 42, which may be made from brass, or other suitable metal that will not be affected by magnetic torque or magnetic attraction. The body portion 42 is formed with a transverse bore 44 having tubular projecting portions 40 and 48 which are internally threaded. Steel cores 5' and 52, having reduced and thread- .and 52. This is. a safety measure in order to insure proper and positive action of the valve in that the cores SI and i2 and the ball 00 may retain a portion 01' the magnetism and the ball would then not release or disengage itseli irom that core to which it was attracted. With the thin portions of the non-magnetic members it and It, the ball will drop as soon as the electric current is disconnected or the circuit is broken.

A tubular fluid pressure conduit 12 is connected to the hexhead end oi the core 52 through a tube nut 14 so that the tubular conduit is inregistry with the conduit 58. Such conduit 12 leads to and provides the pressure line connected to one of the brakes, for example the right brake. A similar fluid conduit It is connected to the core 50 by a tube nut 18 in communication with the conduit 54 and leads to the other brake, namely, the left brake.

A fluid under pressure from the master cylinder i8 is conducted into the interior of the valve ed inner ends, are threadably received within the projections 48 and 48, respectively. The cores ll and 52 are tubular in form, thus providing longitudinally extending channels or conduits I4 and II, respectively, therethrough. Such cores are the cores for the electric coils 58 and 6', respectively, which are wound in the usual manner and disposed at the sides or the valve body portion 42 in embracing and surrounding relation to the core members and I2. The c0res 50 and 52 may be formed from any metal that will become highly magnetized when a current of electricity passes through the coils it and i0.

The valve body 42 is provided with a downwardly directing portion forming a valve cham-- ber 02. A metal plug 54, which is formed of brass or other non-magnetic material, is threadably received within the body portion 42 for providing access to the chamber 02 so that a metal ball valve 06 may be disposed therein which is adapted to be set upon a depressed'portion formed in the inner surface of the plug 84. The ball 6 is formed from a suitable magnetic metal to have the highest magneticattraction obtainable. This ball will rest in its seat in the lower portion of the chamber 02, being held there by gravity until an electric current is produced in either one or the coils 52 and it, at which time the corresponding core 50 or 52 is magnetized to attract the ball ll through aninlet channel ll iormed in an inlet plug 22 formed i'ro'm a non-magnetic metal. Such plug 22 is received within a tapped opening providedin the valve body 42 and communicates with an inlet chamber 24 which is located centrally or the valve body between the inner ends of the cores 50 and I2. Such member 82 is threadably fastened to the end of the master cylinder so that the channel It! is in open communication with the channel 4 i a The outlet end or the member 82 is so formed as to check the fluid pressure entering the core of the member 42 just enough to prevent the metal ball 86 from lifting by the force 0! the fluid and to prevent a straight flow oi fluid and spread it against the side walls of the valve body. This prevents swirling oi the fluid under high velocity and thereby prevents any agitation of the ball I under pressure. To accomplish this the inner end 88 of the valve body is of reduced diameter withrespect to the diameter of the chamber l4 and is provided with a plurality of transversely extending apertures 28 whichare drilled crosswise of the inner end. Thus the fluid under pressure entering through conduit 80 strikes against the battle end 8! and is diverted radially outwardly through apertures 28 into the space between the small end of the plug and the wall 01' the chamber 84.

With the ball in the position shown in It and without energizing either of the coils I! and 60 it will be seen that when the fluid under pressure enters through conduit Ill such fluid under pressure passes throughboth oi the conduits s4 and is to the brake pressure lines It and I2, respectively. However; when it is desired-to make a sharp turn, according to the present invention, means are provided for energizing one of the coils so that fluid to one of the brakes is blocked off and the other brake only will be acted upon to assist in maneuvering, by turning, the tractor.

Such means includes a terminal post so which is electrically connected to the coil 60, and another terminal post 92 which is electrically connected to the coil 5!. Suitable fastener nuts are assassin.

associated with the'posts 90 and 82 for fastening wire connections thereto.

Each of the coils or spools 68 and 60 is provided with end insulating flanges 94 having cylindrcial insulating covers 98 associated therewith so that the coils are encased within insulation. Q

In order to form the ground for the coils 68 and 66, brass washers 88 are interposed between the'inner insulating members 94 and the valve body portion 42. The coils 58 and 60 are electrically connected to the grounds 98 bymeans of metal, electrical conducting members 09 which project through the inner insulating members 64. Ground wires IOI are connected to the 1 members 88 and are suitably grounded as-shown An automatic steering switch I02 (to be. described in detail hereinafter), is provided which is connected through a wire I04 with the termi-' nal 60 of coil 60. The switch is also connected through a wire I06 with the terminal post 92 of the coil 68. A contact I08 connects the switch I 02 with the wire I04; and another contact IIO connects the switch I02 with the wire I06.

An electric storage battery I I2, or other source of electrical power, is provided to energize the coils of the valve I9. Such battery H2 is grounded on one side as indicated at II4 and is connected to the automatic switch through a wire II8 having a knife switch II8 interposed therein.

For a detailed description of the switch I02 reference may be had to Figs. 2 and 3. Such switch. I02 is mounted adjacent the rocker arm of the steering mechanism, as shown in Fig. l, and includes a base I having a coverv I22 associated therewith and connected thereto by means of a post I24 and wing nut I26 to provide a cas- A supporting bracket I28 is mounted to the base I26 and supports thereon spring terminals I36. I32, and I34. The terminals I30 and I32 correspond to the elements I08 and H0, respectively, and are connected to the wires I04 and I 06. respectively. 1

The center spring terminal I84 is connected to the wire II6. Fiber insulation I86 is disposed between the terminals I30, I32 and I84'and also between the top and bottom plates I38. Fiber insulating tubes I extend through apertures in the top plate and abut against the bottom plate and also pass through apertures in the terminals I30, I32, and I34. Clamping screws I42 pass through the members I40 and are threaded into tapped openings in the bottom plate for holding the assembly together.

The controlswitch also includes three leaves I44, I46, and I48. Each of such leaves is provided with a serrated opening therethrough so that the leaves may be fixed upon the serrated portion I of the steering arm shaft I52 to which the arm I4 is also fixed. The members example. The leaves I44, I46, and I48 are formed with arcuate surfaces I64, I66 and I66, respectively. Such surfaces are on arcs of different radii disposed about the center of the shaft I62 with the radiusof leaves I44, I46 and I48 becoming progressivelygreater as clearly shown in Fig. 3. The leaves are suitably displaced with respect to each other about the shaft by angularly positioning them and fixing them in such position on the serrated portion of the shaft through cooperation of the serrated portions of the shaft and leaves. It will thus be seen that the leaves may be positioned in a plurality of different positions with respect to each other which,

position shown in Fig. 3 which is the straight.

ahead position for the vehicle, it will be seen that the projecting end I60 of the spring con tact I34 will be in engagement with the arcuate portion I66 of the leaf I46. When the shaft I62 is rotated in a counter-clockwisedirection, viewing Fig. 3, it will be seen that the projecting end I60 engages the arcuate surface I66 so that the spring contact I34 is urged upwardly making electric contactv with the contact I32. This closes the circuit through the wire I06 and energizes the coil 68 so that the ball 66 is pulled up to close the passageway 64. The fluid under pressure will then enter through the passage 66 to the-right brake. v

When the shaft I62 is turned in a clockwise direction as viewed in Fig. 3. the projection I60 will -be in engagement with the shortest arcuate urface I64, and the spring arm I34 will then contact the terminal I30 to complete the circuit ,through the wire I04 and to energize the coil Manual means is also provided for energizing either of the coils 68 or 60. Such manual means includes a switch frame I10 ,which may be disposed in a convenient location adjacent the operator. Such switch includes a central terminal I12 which is connected to the battery through 'III a wire I14; an end terminal I16 which is connected to the wire I06 through a wire I18; and another end terminal I which is connected to I86 and I88 which extend to positions overlying the ends of the contacts I16 and I80. Plungers I60 and I82 are slidably mounted in the frame I10 adjacent the ends of portions I86 and I88, respectively. By depressing either of the members I00 or I82, the corresponding end I86 and I68 will be urged against its contact I16 or I80. When the circuit is closed through contact I16, it will be appreciated that the coil 56 is energized; or when the plunger I62 is depressed the circuit through contact I80'would be closed to energize the coil 60.

The construction just described provides a manual means ioroperating the valve is without the'need or the automatic steering switch I02.

What is claimed is: I. In a tractor having a pair of rear-wardly positioned driving wheels, one on each side thereof,

a front dirigible wheel, means for turning said dirigible wheel at an angle to the driving wheels to steer the tractor, an hydraulically actuated brake on each 01' said driving wheels, a brake master cylinder, a separate fluid connection between said master cylinder and each brake, and magnetic valve means interposed in the connection between said master cylinder and each said brake, said valve means including an inlet associated with said master cylinder, an outlet conduit associated with each of said separate fluid connections, means for magnetizing each of said outlet conduits, said valve means including an e element responsive to the magnetizing of either oi. said outlet conduits to block the flow of fluid therethrough, and electric means operatively con necting said valve means with said turning means so that said magnetic valve means is energized when said dirlglble wheel is turned beyond a predetermined angle.

2. In a tractor having a pair of rearwardly positioned driving wheels, one on each side thereor, a front dirigi-ble wheel, means for turning said dirigible wheel at an angle to the driving wheels to steer the tractor, an hydraulically actuated brake on each-oi said driving wheels, a brake master cylinder, a separate fluid connection between said master cylinder and each brake,

and magnetic valve means interposed in the connection between said master cylinder and said brakes, said valve means including an inlet associated with said master cylinder, an outlet conduit associated with each 01' said separate fluid connections, independent means for magnetizing each of said outlet conduits, said valve means including an element responsive to the magnetizing oi either of said outlet conduits to block the flow oi fluid therethrough, and means to render efiective said independent means operable in response to the turning oi said dirigible wheel when said dirigible wheel is turned av predetermined angle with respect to the rear wheels.

3. In a tractor having a pair of rearwardly positioned driving wheels, one on each side theretion between said master cylinder and each brake.

and magnetic valve means interposedin the con- 1 nection between said master cylinder and said brakes, said valve means including an inlet asor, a front dirigible wheel, means for turning said dirigible wheel at an angle to the driving wheels to steer the tractor, an hydraulically actuated brake on each oi" said driving wheels,a brake master cylinder, a separatev fluid connection between said master cylinder and each brake, and magnetic valve. means interposed in.

the connection between said master cylinder and each said brake, said valve means including an inlet associated with said master cylinder," an

outlet conduit associated with each of said sep-" arate fluid connections, electric coils embracing said outlet conduits tor magnetizing such conduits, means operatively connecting said valve and said turning means for energizing said coils when said dirigible wheel is turned beyond a predetermined-angle, and said valve means includin: a magnetically attracted element responsive sociated with said master cylinder, an outlet conduit associated with each of said separate fluid connections, electric coils embracing each of said outlet conduits for magnetizing such conduits, means for energizing said coils, said valve means including an element responsive to the magnetizing of either of said outlet conduits to block the flow oi fluidtherethrough, and means to render efiective said energizing means operable in response to the turning of said dirigible wheel when said dirigible wheel is turned a predetermined angle with respect to the rear wheels.

5. In a tractor having a pair of rearwardly positioned driving wheels, one on each side thereof, a frontdirigible wheel, means 'for turning saizi dirigible wheel at an angle to the driving wheels to steer the tractor, an hydraulically actuated brake on each .01 said driving wheels, a brake master cylinder, a separate fluid connection between said master cylinder and each brake, and magnetic valve means interposed in the connection between said master cylinder and each said brake, said valve means including an inlet associated with said master cylinder, an outlet conduit associated with each of said separate fluid connections, independent means operatively connecting said valve and turning means for magnetizing 'each' of said outlet conduits, and said valve means including an element responsive to the magnetizing of either 01' said outlet conduits to block the flow of fluid therethrough.

6. In a tractor having a pair of rearwardly positioned driving wheels, one on each side thereof, a front dirigible wheel, means for turning said dirigible wheel at an angle to the driving wheels to steer the tractor, an hydraulically actuated brake on each of said driving wheels, a brake master cylindena separate fluid connection between said master cylinder and each brake. and magnetic valve means interposed in the connection between said master cylinder and said brakes, said valve means including an inlet associated with said master cylinder, an outlet conduit associated with each of said separate fluid connections, independent means for magnetizing HOMER T. LAMBERT. 

